In the art of selectively plating specific areas of a metal such as the formation of lead frames or the application of contacts to connectors, it is a common practice to provide a metal strip which is indexed into position and stopped. A rubber gasket material on a rigid support is forced tightly against one surface of the metal strip and an apertured plating mask contacts an opposite surface of the metal strip. The apertured plating mask forms a seal with the metal strip and a plating solution is applied to the selected areas of the metal strip through the apertures of the apertured plating mask. Following, the rubber gasket material and the apertured plating mask are moved away from the metal strip which is indexed forward and the cycle repeated.
Although the above-described process and apparatus for plating specific areas of metal have been and still are utilized in numerous applications, it has been found that there are other applications which require revisions and adjustments to the known and established techniques. For example, it has been found that the deposition of silver on a specific area of copper requires enhanced apertured mask to metal sealing but will not tolerate undue distortion of the metal due to added pressure.
On the one hand, an apertured mask which is relatively rigid, such as a glass-filled epoxy mask for example, does not provide the necessary mask to metal sealing and offers little or no opportunity for mask repair due to wear or damage. On the other hand, an apertured mask which is relatively soft, such as a mask having a soft rubber sheet covering, tends to lack the necessary toughness for repetitive use and deform under operational pressure and temperature conditions. Moreover, the relatively soft material undesirably exhibits relatively rapid wear characteristics which offer little or no repair capabilities.